This invention relates to optical deflectors and to systems incorporating such optical deflectors.
The demand for information has grown tremendously in the past few decades, leading to an increased demand for communication capability. Naturally, this increased demand for communication capability is accompanied by an increase in demand for information storage capability. The increased demand for communication capability is at least partly met by optical communication systems that use a network of fiber optic cables. As for the increased demand for optical storage capability, much research is being done to provide an optical storage media that allows storage of more data and easy access of the stored data.
Optical storage media that use light to store and read data have been the backbone of data storage for about two decades. Among various optical storage media, CDs and DVDs are the primary data storage media for music, software, personal computing and video. CDs, DVDs and magnetic storage all store bits of information on the surface of a recording medium. A typical CD can hold 783 megabytes of data, which is equivalent to about one hour and 15 minutes of music. Some special high-capacity CD can hold up to 1.3-gigabyte (GB) of data, and a double-sided, double-layer DVD can hold 15.9 GB of data, which is about eight hours of movies. These storage mediums meet today's storage needs, but storage technologies have to evolve to keep pace with increasing consumer demand.
In order to increase storage capability, scientists are now working on a new optical storage method frequently called holographic memory. Unlike CDs and DVDs that store data only on the disc surface, holographic memory stores data three-dimensionally, in the volume of the recording medium in addition to the surface area of the disc. Three-dimensional data storage stores more information in a given volume and offers faster data transfer times.
However, holographic memory technology has its problems. For example, angular multiplexed holographic memory systems are facing obstacles in the area of dynamic control of two dimensional page oriented data. The root of these obstacles is that currently existing page-addressing deflectors require a moving mechanical optical assembly that cause poor stability and throughput rate. In order to mass-store high density images and access them fast without any moving parts, an innovative page-addressing deflector free of moving parts is required. High-speed electro-optic beam deflectors can significantly improve the performance of the volume holographic memory based on angular multiplexing techniques.
A reliable holographic memory system with large capacity and high throughput rates would find commercial applications in telecommunication, large database storage and processing and other applications. Furthermore, the electro-optic (EO) beam deflectors used in the holographic memory would be used in laser printers, optical computing, laser communication systems, optical sensors, and optical switching networks. A reliable EO deflector with large deflecting angle at low driving voltage, fast slew rate, light weight, simplified fabrication scheme, and compact structure would be advantageous whenever there is a need for low power fast optical beam steering.